What the heck kind of steel is this?!?

[mitch8]

I got these blade from a corrugate cardboard cutting place. They said these are for some operation at the end of the cardboard proses, can't remember what though. I want to know what kind of steel it is because I have some plans for forging it into a knife of its an easy to work with steel. Anyway here are some pictures of the half if that helps.

[mitch8]

ok cant get the pix to work but for now its a disk with these specs
7/32 inch thick
10 5/8 inch outside diameter
7 11/16 inch inside diameter
6 holes each 7/16 dia.
otherwise thats all i got. any idas about the steel type or how to post pictures?

thanks, mitch

[stevomiller]

Mitch,
Some sort of tool steel is about as good as you will get, no way to tell and guessing doesn't work. The only way to know for sure would be if it had the make and model of cutter, and then the company was willing to tell you what they used. Very real chance it's an air hardening steel, which pretty much takes forging out of the picture.
Suggestion? Buy some 1084, 1095, or 5160 if you want to forge something.

[OldCABear]

ok cant get the pix to work but for now its a disk with these specs
7/32 inch thick
10 5/8 inch outside diameter
7 11/16 inch inside diameter
6 holes each 7/16 dia.
otherwise thats all i got. any idas about the steel type or how to post pictures?

thanks, mitch

Okay Mitch, Starting from scratch I suggest the first thing you do is search the web for an old machinist steel hardness determination method called Spark Testing. A good site will give you clear color shots of the kind and color of sparks produced on a given material and grit grinding wheel by various hardness degrees of the steel you wish to test. Some steel types will produce significantly different spark patterns as will different hardnesses. The depth of the test grind may change color and pattern should the steel be surface hardened by one method or another. The second thing I would do is find an old Machinist's handbook, there are two significant publications out there. I have both Machinery and American Machinist and prefer my American since it was published in the late 40s and contains a bunch of legacy knowledge applicable to the old school machinist trade. I'd get at least one of them to learn about annealing, forging, heat treating and steel types. I'd do that even if you decide to take your product to a professional. And that's my 2 cents worth.

[mitch8]

well i only have half of the disc, i got it for free at a garage sale. the only marking i can find on my half is a corroded 802 or 302. to far gone to tell. but the american machinist handbook has steel identification info? cause my heat treating book doesnt. and would a book from the 40s have all the steels that we use today?

[aarongb]

Bottom line, no one knows what kind of steel you have, except possibly the manufacturer. A spark test can't be compared to line drawings in a book, you need at least one control sample (a known steel) and equal pressure against the wheel across all the samples as you "read" the sparks to have any idea what you might possibly have. It's not a beginner task, and I wouldn't trust the word of a pro either. This is because a 4' bar of 1084, a known steel suitable for forging, stock removal and simple heat treat costs about $20, including shipping. With the time, effort and research it will take you to determine that steel type, you could already be working. If this steel was personal and sentimental for some reason, all that guesswork and testing might be valuable.

[amamachinist]

well i only have half of the disc, i got it for free at a garage sale. the only marking i can find on my half is a corroded 802 or 302. to far gone to tell. but the american machinist handbook has steel identification info? cause my heat treating book doesnt. and would a book from the 40s have all the steels that we use today?

If you have a machinerys handbook from the 40's I'll buy it from you and you can buy plenty of good knife steel with it!

[bladsmth]

Mitch - As said there is no way to know what steel it is.

Old CABear - The steels in the late 1800's and early 1900's, when that data was gathered, were far simpler than today. Now we have so many alloys, and modified alloys, that a simple spark test won't tell you too much. It is only useful if you already know what you think the steel is. Say you pick up a bar on your bench and can't' remember if it is 1095 or 5160? A spark test will tell you which it is ( especially if you have other bars of each from the same source). But if you pick up a bar of steel at a yard sale, the spark test won't give you enough info the determine the make-up to do a proper HT. It might indicate carbon steel, or high alloy...but which alloy or which carbon steel??????

[mitch8]

I got another blade from the same factory that was thinner and labled zenith. Called in and they said it was 52100. Any chance this is the same stuff? That would be great if it was.

[SteelSlaver]

Well you could grind both and see if they spark the same or heat treat a piece with 52100 heat treat and see how it comes out.

Or you could get a 4 ft bar of 52100 from Aldo. 3/16" thick and 1 1/2" wide for less than $25 and know exactly what you have in a shape you could easily grind 5 or 6 knives from.

[bladsmth]

ib2v4u is giving good advice.